Deliberately shifting each layer by a specified amount

I want to create an offset of a fraction of a mm in X and Y for each layer in a gcode file.

Is there an easy way to do that using the custom end of layer gcode entry in slic3r or do I need a post processor that will add an offset equal to the incremental offset x the layer number to the X and Y coordinates in the file?

Thanks!

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

In RepRapFirmware it's easy, because there is the M556 command to do exactly that.

Otherwise, you could try a layer change script something like this:

G1 X0 Y0 F10000
G92 X0.1 Y0.1

If slic3r doesn't insert a command to move back to the correct XY position after running the layer change script, then you may be out of luck.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I'm doing this to operate a coreXY mechanism as a drawbot without pen lift capability (yet) so returning to home for each layer would draw an extra line at each layer change. I'm looking into adding a solenoid to lift the pen, then it's all good.

Thanks.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

FWIW we're adding a relative option in the RepRapFirmware implementation of the G92 command in the next release, but that won't help you if you are running other firmware - unless your firmware already supports relative G92.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
the_digital_dentist
I'm doing this to operate a coreXY mechanism as a drawbot without pen lift capability (yet) so returning to home for each layer would draw an extra line at each layer change. I'm looking into adding a solenoid to lift the pen, then it's all good.

Thanks.

Sounds intriguing - what sort of pen drawing has multiple layers? Also not sure why you would need to home for each layer. If your XY table cannot keep its position from layer to layer, then surely that needs to be fixed?

Dave

You have misunderstood. I don't want it to return to home at the start of each layer, I want to avoid the necessity of doing that. I am using the CoreXY mechanism for a 3D printer as a high precision drawbot. I will feed it gcode files because it has a 3D printer controller board that understands them. Imagine printing a cylinder where you have a pen instead of an extruder and there is no Z axis. You'll end up printing circles and the gcode runs. The mechanism doesn't know it has a pen and that there's no Z axis, so when a layer change occurs in the gcode file, the pen stays on the paper and keeps drawing. How many times can the pen overwrite the same circle before it chews a hole in the paper? By adding a small shift to the position of each layer the pen will draw on a fresh paper most of the time and generate some interesting interference patterns in the process, depending on the gcode being 'printed'.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]